Automatic dead bolt latch



Aug. 4, 1942. R. c. CERF AUTOMATIC DEAD BOLT LATCH 4 Filed May 5, 1941 2 Sheets-Sheet 1 Aug. 4-, 1942. Q CERF 2,291,878

AUTOMATIC DEAD BOLT LATCH Filed May 5, 1941 2 Sheets-Sheet 2 Patented Aug. 4, 1942 AUTOMATIC DEAD BOLT LATCH Robert C. Cerf, Los Angeles, Calii'., assignor to Pacific Plastic & Manufacturing Company, Inc., Los Angeles, Calif., a corporation of California Application May 5, 1941, Serial No. 391,880

6- Claims.

This invention relates to door latches and more particularly to the type of door latches having an auxiliary latch bolt adapted, upon being retracted, to securely lock the main latch bolt against dislacement by means of jimmies and similar tools.

It is one object of this invention to provide such a latch which will be simple and economical of construction.

It is another object of this invention to provide such a latch in which, by means of the elimination of the use of links and chains, durability and strength is achieved.

It is a further object of this invention to provide a latch of the type described which is completely reversible, thus enabling one latch to be used for either right hand or left hand installations.

Further objects and advantages of this invention will appear hereinafter.

In the accompanying drawings:

Fig. 1 is a. horizontal section showing a preferred embodiment of my invention as secured to a door and illustrating the locking mechanism and knob as applied thereto.

Fig. 2 is a section taken on the line IIII of Figure 1.

Fig. 3 is a fragmentary section illustrating a portion of my invention and taken on the line IIII1'I of Figure 2.

Fig. 4 is a view similar to Figure 2, partly in section, and illustrating the parts in locked position.

Fig. 5 is a section taken on the line V--V of Figure 4.

Fig. 6 is an elevation of the auxiliary latch bolt employed in my invention.

Fig. 7 is an elevation of the locking bar used in my invention.

Fig. 8 is a plan view of half of the tubular casing employed in my invention.

Fig. 9 is a plan view of the main latch bolt employed in my invention, also showing the relative position of the hub.

Fig. 10 is a plan view of the cover portion of the tubular casing. I

Referring more particularly to the drawings, I have illustrated a latch including a tubular casing I0 composed of two halves I00. and Illb, Figures 8 and 10. Referring especially to Figure 1, it will be noted that, the tubular casing I0 is flattened on each side as at I l and is provided with four holes I2 extending therethrough. A conventional locking mechanism I3 adapted to be actuated by a key I4 is provided. The locking mechanism I3 in the holes I5 of the locking mechanism I3 and secures the locking mechanism to the door and in alignment with the latch.

The locking mechanism I3 is provided with a conventional spindle I9 adapted to be actuated in response to rotation of the key I4. Upon the other end of the spindle IS a knob 20 may be secured.

The spindle I9 is adapted to project through the hub 2|, later to be described; ofthe latch mechanism, while the bolts I8 may pass through either of the holes I2 of the tubular casing.

By means of the provision of the plurality of holes I2 in the casing, it is possible to completely reverse the latching mechanism, in one position of which the two bolts I 8 will be secured through the upper of the holes I2 in the latch casing and in the other position the bolts l8 will be secured through the lower of the holes I2. Thus I have enabled one latch to be used, according to necessity, either for right hand or left hand installation.

The tubular casing I 0 encloses a main latch bolt 22. This main latch bolt 22 is formed, as particularly illustrated in Figure 9, having a projecting portion 23 beveled in the usual manner and flattened upon one side and having a portion extending rearwardly into the casing, which is tubular in form, back to the shoulder 24 and having two arms extending rearwardly therefrom as at 25. The arms 25 are notched as at 26 to form a rack. In operation the bolt 22 lies within the casing II] with one end projecting therefrom and is adapted to slide in said casing.

An auxiliary bolt 21 is provided, formed as shown particularly. in Figure 6, and consisting generally of a rod flattened on one side and having a shoulder 28 upon the inward end thereof. A hole 29 is drilled in the latch 21 to accommodate the spring 30.

The cover lb of the casing I 0 has a pin 3| extending from the shoulder 32 formed by the flattened portion II. This pin 3| is adapted to be surrounded by and carry a portion of the spring 30. The hub 2| is provided with a cam 33 and gear teeth 34 formed thereon. The hub H has a square hole formed therein adapted to be engaged by the spindle I9 as hereinbefore described. The gear teeth 34 are formed upon the forward portion only of the hub 2| and are adapted to alternately engage one or the other of the racks 26. Rotation of the hub by means of the spindle I9 will, therefore, cause the gear teeth 34 to engage the rack 26 and retract the main latch bolt 22. In the portion Illa of the tubular casing l0, about midway therein, there is constructed an upstanding shoulder 35. A boss 36 is formed thereon about which is pivoted a locking member 31. The locking member 31 is formed in the irregular shape illustrated in Figure 7 and carries on one end thereof a cam follower 38 adapted to engage the cam 33 and in one position thereof to fall into the notch 33a of said cam 33. The other end of the locking mechanism 31 consists of an arm 39 having a flattened end 40. A flange 4| is formed on the locking member 31 adapted to be engaged by a spring 42 which is positioned in a hole 43 in the portion |a of the tubular casing. By reference to Figure 3 it will be noted that the spring 42 will bear upon the shoulder 4| and normally tend to urge said locking mechanism towards locked position. A coil spring 44 is positioned within a hole 44a in the main latch bolt 22 with one end thereof abutting upon the shoulder 35, thereby normally urging said main latch bolt 22 towards its extended position Said main latch bolt 22 has a channel 45 therein to accommodate the auxiliary latch bolt 21. The shoulder 28 of the auxiliary latch bolt 21 engages the shoulder 24 of the main latch bolt 22 and is, therefore, repressed coincident to the repressing of the main latch bolt 22.

Said main latch bolt 22 has a slot 46 formed therein, as clearly shown in Figure 5. The arm 39 of the locking member 31 extends toward the shoulder 24 of the main latch bolt 22 and in its open position lies within the slot 46 in said latch bolt. In locked position, however, said arm 39 does not lie in alignment with or within said slot 45 but lies at least partially directly behind the shoulder 24 on said latch bolt 22, thereby securing said main latch bolt from being repressed by any force applied upon the outer end thereof.

The shoulder 28 of the auxiliary latch bolt 21 extends downward into the path of the locking member 31 and is adapted to engage the beveled portion 41 of the arm 39, thereby forcing said arm 39 away from its position behind the shoulder 24 of the bolt 22 and into alignment with the slot 46, thereby permitting retraction of said main latch bolt 22.

The operation of the mechanism is as follows:

Upon the closing of the door, the latch bolt 22 will engage the striker plate 48 and become retracted, at the same time retracting the auxiliary latch bolt 21. Upon aligning with the opening 49 in said striker plate, however, the main latch bolt 22 will move forward under the force of the spring 44. The auxiliary latch bolt 21, however, will still remain engaged by a portion of the striker plate 48 and will, therefore, remain in its retracted position. With the auxiliary latch bolt 21 in its retracted position, the shoulder 28 thereof will be removed from engagement with the beveled portion 41 of the arm 39 of the locking member 31, thereby enabling the locking member 31 to move under the force of the spring 43 into position so that the squared end 40 lies behind a portion of the latch bolt 22 at the shoulder 24. Thus the main latch bolt 22 will be securely held against retraction by any unauthorized force.

When it is desired to open the door, the spindle I9 is rotated either by the key M or the knob 20, thereby rotating the hub 2|. The cam 33 formed on the hub 2| rotates therewith and the cam follower 38 of locking member 31 will be forced from the notch 3341, thereby moving said locking member 31 into the position in which the arm 39 thereof lies in alignment with the slot 46. Further rotation of the hub 2| will bring one or more of the gear teeth 34 into operating contact-with one or the other of the racks 26, thereby withdrawing the main latch bolt 22.

The casing member Ilia is provided at its forward end with a circular portion 50 with openings therein fitting the flattened portion of main latch bolt22 and also auxiliary bolt 21. The forward shoulder of main latch bolt 22 will engage said portion 50 and limit further projection of the bolts from the casing l0.

The cover lOb is suitably secured to the casing portion Illa by screws inserted in holes 52 and 53 and threading into threads formed in member Illa at 54 and within boss 38 as at 55. A lug 56 on cover lllb is adapted to lie in notch 51 of portion 58 to more completely secure correct alignment and assembly of the cover and casing.

By reason of the locking mechanism I3 and knob 20 being secured to the casing ID by bolts l8, positive alignment of these members is secured.

As will be observed by anyone skilled in the art, all parts of my latch and lock may be installed in the door without the necessity of mortising the door, as holes drilled to accommodate the tubular casing I0 and lock l3 will suffice.

From the foregoing description, it will be seen that I have provided a latch incorporating an automatic dead bolt and I have avoided the use of such easily destructible elements as links, chains, etc. The entire motion of the parts of this mechanism centers about the hub 2| and is controlled by rotation thereof, thus providing a simple, compact and durable latch mechanism.

While the particular forms of the invention herein described are well adapted to carry out the objects of the invention, it is to be understood that various modifications and changes may be made without departing from the principles of the invention, and the invention includes all such modifications and changes as come within the scope of the appended claims.

I claim:

1. In an automatic dead bolt latch of the character described, the combination of a tubular casing, a main latch bolt and an auxiliary latch bolt mounted therein and adapted to project from said casing, a locking member pivotally mounted intermediate its ends, a hub, a cam formed upon said hub, spring means normally urging said locking member towards locking position, means upon said auxiliary bolt adapted to engage said locking member and retain said locking member out of locking position when said auxiliary bolt is extended, rack means upon said main latch bolt adjacent said hub and on both sides thereof, gear teeth upon said hub adapted to engage said rack means to retract said main latch bolt upon rotation of said hub in either direction, a cam follower upon said locking member adapted to move said locking member out of locking position when said hub is rotated, said gear teeth being spaced upon said hub so as to permit rotation of said hub to clear said cam follower to unlocked position prior to engagement of said gear teeth with said rack means.

2. In an automtaic dead bolt latch of the character described, the combination of a tubular casing, a main latch bolt and an auxiliary latch bolt mounted therein and adapted to project from said casing, a locking member pivotally mounted intermediate its ends, a hub, a cam formed upon said hub, spring means normally urging said locking member towards locking position, means upon said auxiliary bolt adapted to engage said locking member and retain said locking member out of locking position when said auxiliary bolt is extended, rack means upon said main latch bolt adjacent said hub and on both sides thereof, gear teeth upon said hub adapted to engage said rack means to retract said main latch bolt upon rotation of said hub in either direction, a cam follower upon said locking member adapted to move said locking member out of locking position when said hub is rotated, said gear-teeth being spaced upon said hub so as to permit rotation of said hubto clear said cam follower to unlocked position prior to engagement of said gear teeth with said rack means, a key actuated locking mechanism secured to said casing and having a spindle adapted to rotate said hub, and means for securing said key actuated locking mechanism to said casing when said casing is positioned for either right hand or left hand use.

3. In an automatic dead bolt latch of the character described, the combination of a tubular casing, a main latch bolt and an auxiliary latch bolt mounted therein and adapted to project from said casing, a locking member pivotally mounted intermediate its ends, a hub, a cam formed upon said hub, spring means normally urging said locking member towards locking position, a slot in said main latch bolt in alignment with said locking member when said locking member is out of locking position to accommodate said locking member when said main latch bolt is repressed, means upon said auxiliary bolt adapted to engage said locking member and retain said locking member out of locking position when said auxiliary bolt is extended, rack means upon said main latch bolt adjacent said hub and on both sides thereof, gear teeth upon said hub adapted to engage said rack means to retract said main latch bolt upon rotation of said hub in either direction, a cam follower upon said locking member adapted to move said locking member out of locking position when said hub is rotated, said gear teeth being spaced upon said hub so as to permit, rotation of said hub to clear said cam follower to unlocked position prior to engagement of said gear teeth with said rack means.

4. In an automatic dead bolt latch of the character described, the combination of a tubular casing, a main latch bolt and an auxiliary latch bolt mounted therein and adapted to project from said casing, a locking member pivotally mounted intermediate its ends, a hub, a cam formed upon said hub, spring means normally urging said locking member towards locking position, a slot in said main latch bolt in alignment with said locking member when said lockin member is out of locking position to accommodate said locking member when said main latch bolt vis repressed, means upon said auxiliary bolt adapted to engage said locking member and retain said locking member out of locking position when said auxiliary bolt is extended, rack means upon said main latch bolt adjacent said hub and on both sides thereof, gear teeth upon said hub adapted to engage said rack means to retract said main latch bolt upon rotation of said hub in either direction, a cam follower upon said locking member adapted to move said locking member out of locking position when said hub is rotated, said gear teeth being spaced upon said hub so as to permit rotation of said hub to clear said cam follower to unlocked position prior to engagement of said gear teeth with said rackmeans, a key actuated locking mechanism securedto said caslag and having a spindle adapted to rotate said hub, and means for securingsaid key actuated locking 7 mechanism to said casing when said casing is positioned for either right hand or left hand use.

5. In an automatic dead bolt latch of the character described, the combination of a tubular casing, a main latch bolt and an auxiliary latch bolt mounted therein and adapted to project from said casing, a locking member pivotally mounted intermediate its ends and adapted in looking position to have one of its ends positioned directly behind a portion of said main latch bolt to prevent repression thereof, a hub, a cam formed upon said hub, spring means normally urging said locking member towards locking position, a slot in said main latch bolt in alignment with said locking member when said locking member is out of locking position to accommodate said locking member when said main latch bolt is repressed, means upon said auxiliary bolt adapted to engage said locking member and retain said locking member out of locking position when said auxiliary bolt is extended, rack means upon said main:

latch bolt adjacent said hub and on both sides thereof, gear teeth upon said hub adapted to engage said rack means to retract said main latch bolt upon rotation of said hub in either direction, a cam follower upon said locking member adapted to move said locking member out of locking position when said hub is rotated, said gear teeth being spaced upon said hub so. as to permit rotation'oi said hub to clear said cam follower to unlocked position prior to engagement of said gear teeth with said rack means.

6. In an automatic dead bolt latch of the character described, the combination of a tubular casing, a main latch bolt and an auxiliary latch bolt mounted therein and adapted to project from said casing, a locking member pivotally' mounted intermediate its ends and adapted in looking position to have one of its ends positioned directly behind a portion of said main latch bolt to prevent repression thereof, a hub, a cam formed upon said hub, spring means normally urging said locking member towards locking position, a slot in said main latch bolt in alignment with said locking member when said locking member is out of locking position to accommodate said locking member when said main latch bolt is repressed, means upon said auxiliary bolt adapted to engage said locking member and retain said locking member out of locking position when said auxiliary bolt is extended, rack means upon said main latch bolt adjacent said hub and on both sides thereof, gear teeth upon said hub adapted to engage said rack means to retract said main latch bolt upon rotation of said hub in either direction, a cam follower upon said locking member adapted to move said locking member out of locking position when said hub is rotated, said gear teeth being spaced upon said hub so 'as to permit rotation of said hub to clear said cam follower to unlocked position prior to engagement of said gear teeth with said rack means,

left hand use.

RQBERT C. C. 

